Biological diversity of the Minnesota caddisflies (Insecta, Trichoptera)

Does land use and land cover affect adult communities of Ephemeroptera, Plecoptera and Trichoptera (EPT)? A systematic review with meta-analysis

We conducted a systematic review to better understand this gap and analyzed i) in which global regions are studies usually conducted, ii) the taxon studied, iii) sampling methods and iv) how authors collaborated in these studies. We also tested the relationship between different types of land use and land cover and adult EPT communities using a meta-analysis. We searched for relevant articles on the website Web of Science, using specific words related to the subject. We found 454 papers and selected 31 of them for the scientometric analysis, as they were in accordance with our objectives, and eight for the meta-analysis. Among this subset, we observed that study areas and collaborations among authors were largely restricted to a few countries in Europe and North America. Most studies used the group Trichoptera, probably due to its diversity and the longevity of the adults compared to other groups. Light traps were the most common sampling method, most likely due to their efficiency in capturing flying insects with nocturnal habits. The greatest differences in adult EPT communities were found between open areas (moorland and prairie) and forest areas. This result indicated that the conversion of forest habitats into open areas negatively impacts adult EPT communities. Our systematic review can be an important tool to help researchers choose appropriate collection methods and taxonomic groups to work with in studies on impacts of land use change on adult EPT communities.

An Ecological Profile of Hydropsyche alternans (Trichoptera: Hydropsychidae) in Lake Superior, the Last Stronghold of a Once-Dominant Great Lakes Surf Zone Caddisfly

Simple Summary

Prior to the invasion and spread of Dreissena mussels in the late 1980s, the nearshore waters of the Laurentian Great Lakes were home to diverse assemblages of native aquatic insects, including the net-spinning caddisfly Hydropsyche alternans, which occurred in rocky surf-exposed habitat throughout the system from Lake Superior downstream to Lake Ontario. These surf zone caddisflies are still abundant in the largely Dreissena-free waters of Lake Superior where the present study was conducted. They have not been reported in the lakes below Lake Superior for decades, and are presumed to have been extirpated from Dreissena-infested habitats. The ecological profile presented here documents the life history of H. alternans in Lake Superior, and reveals details of its feeding biology that shed light on the roles that surf zone net-spinners play in the native nearshore food webs of the Great Lakes. The H. alternans life history in Lake Superior begins in mid-summer shortly after oviposition, which features females swimming to surf-exposed lake bottom substrates. Larval development takes approximately 10 months, but most of it occurs during their first 100 days. Adult emergence is broadly synchronous, with large numbers present from the summer solstice through mid-July. Gut content analyses showed that larvae opportunistically feed on algal, animal, and detrital material of aquatic and terrestrial origin. δ¹³C and δ¹⁵N stable isotope data indicate that they function as omnivores that link coastal, nearshore, and pelagic food webs. These energetic links, and the very existence of surf zone insect assemblages in the Great Lakes, depend on the Dreissena populations in Lake Superior remaining relatively small and isolated.

Abstract

We studied the life history, diet, and trophic ecology of Hydropsyche alternans in four rocky sites located along the south-central coast of Lake Superior. The H. alternans life history and broad trophic niche space were similar to those of its riverine relatives. Quantitative sampling over the course of one ice-free season revealed that most individuals lived univoltine life histories that featured early to mid-summer mating, and oviposition and rapid growth and development through summer into fall. Most individuals overwintered as ultimate or penultimate larval instars. Pupation followed ice-out in the spring. Gut content sampling and δ¹³C and δ¹⁵N stable isotope analyses indicated that the typical larval diet is a mix of benthic, pelagic, and terrestrial food resources, including diatoms, small arthropods, sloughed periphyton, and in one site, fugal hyphae apparently of foredune origin. As a suspension-feeding omnivore that relies on waves and currents to deliver food to its nets, H. alternans larvae form energetic links between coastal, nearshore, and offshore food webs. These connections have been lost throughout the lower Laurentian Great Lakes as a consequence of the invasion and spread of Dreissena mussels.

Comparison of caddisfly (Insecta, Trichoptera) assemblages from lake and river habitats of the Huron Mountains of Michigan (USA)

The caddisfly assemblages of six lakes and 12 1st-4th order streams of the Huron Mountains of northern Upper Michigan (USA) were sampled monthly with ultraviolet lights during June-September 2019. A total of 169 species representing 63 genera and 19 families was collected, including five species not found elsewhere in Michigan and two species endemic to the state. Species assemblages between lotic and lentic habitats were distinct from each other, with 11 species indicating lakes and 23 indicating rivers. Despite the taxonomic differences, biomass of functional feeding groups (FFGs) was similar between lakes and rivers, except for higher biomass of predators in the former and higher biomass of filtering collectors in the latter. The FFG biomass of both habitat types was dominated (50-70%) by shredders. Considering the undisturbed condition of the habitats, the caddisfly assemblages and FFG biomass of the Huron Mountains can serve as regional biological monitoring reference conditions.

Checklist of the caddisflies (Insecta, Trichoptera) of the Upper Midwest region of the United States

Five hundred and fifty-two caddisfly species are reported from the Upper Midwest region of the United States, an area that includes 13 states and ~ 2 million km². Of these, 62 species are reported for the first time from the state of Iowa, 25 from Wisconsin, 18 from South Dakota, 12 from Illinois, five from Indiana, four from North Dakota, four from Minnesota, and one from Nebraska. The Upper Midwest fauna contains nearly 40% of all species known from the United States and Canada, as well as 22 species endemic to the region. Overall species richness was highest in Michigan (319 species), Kentucky (296), Minnesota (292), and Wisconsin (284). Differences in state species assemblages within the region largely followed a geographic pattern, with species richness declining in the western prairie states. There are almost certainly further species remaining to be found in this large region.

Updated checklist of the Michigan (USA) caddisflies, with regional and habitat affinities

Based on examination of ~180,000 specimens from 695 collections of 443 localities collected from the 1930s to 2015 we report 295 species of caddisflies from Michigan. Of these, 41 are reported from the state for the first time. Another 18 species previously reported from Michigan are listed as doubtful. The 11 most abundant species collectively represented over half of all specimens collected. Conversely, 80 species were known from <10 specimens, and 27 species from a single specimen. The Michigan fauna is similar to those of Minnesota and Ohio, adjacent states with comparable recent collecting effort. Regional and habitat affinities for each Michigan species are reported herein. Due to the high level of species discovery over the last few years, despite a >80-year collecting history, it is likely that additional species remain undiscovered in the state.

A relative contribution of carbon from green tide algae Cladophora glomerata and Ulva intestinalis in the coastal food webs in the Neva Estuary (Baltic Sea)

We analyzed stable isotope composition of carbon and nitrogen of suspended organic matter (seston) and tissues of macroalgae, macroinvertebrates and fish from the coastal area of the highly eutrophic Neva Estuary to test a hypothesis that organic carbon of macroalgae Cladophora glomerata and Ulva intestinalis produced during green tides may be among primary sources supporting coastal food webs. The Stable Isotope Bayesian mixing model (SIAR) showed that consumers poorly use organic carbon produced by macroalgae. According to the results of SIAR modeling, benthic macroinvertebrates and fish mostly rely on pelagic derived carbon as a basal resource for their production. Only some species of macroinvertebrates consumed macroalgae. Fish used this resource directly consuming zooplankton or indirectly via benthic macroinvertebrates. This was consistent with the results of the gut content analysis, which revealed a high proportion of zooplankton in the guts of non-predatory fish.

Support in Clinical Settings as Perceived by Nursing Students in Iran: A Qualitative Study

Background

Although support is one of the most substantial needs of nursing students during clinical education, it is not clearly defined in the literature.

Objectives

The current study aimed to explore the concept of support in clinical settings as perceived by nursing students.

Materials and Methods

A qualitative content analysis was used to explore the meaning of student support in clinical settings. A purposive sampling with maximum variation was used to select the participants among bachelor nursing students in the nursing school of Babol University of Medical Sciences in the north of Iran. Semi-structured interviews were conducted to gather the perceptions and experiences of seventeen nursing students. Conventional content analysis was applied to analyze the data.

Results

In the current study, the main theme, nurturance, was emerged with seven subthemes of humanistic behavior with the student, respectful communication with students, accepting the student in the clinical setting, sustaining confidence, need based supervision, accepting the profession in the society and empowerment.

Conclusions

Nursing students support in the clinical education requires a nurturing care; a care that leads to the sense of worthiness and respectability in students and contributes to the improvement of their clinical abilities.

Mayflies, stoneflies, and caddisflies of streams and marshes of Indiana Dunes National Lakeshore, USA

United States National Parks have protected natural communities for one hundred years. Indiana Dunes National Lakeshore (INDU) is a park unit along the southern boundary of Lake Michigan in Indiana, USA. An inventory of 19 sites, consisting of a seep, 12 streams, four marshes, a bog, and a fen were examined for mayflies (Ephemeroptera), stoneflies (Plecoptera), and caddisflies (Trichoptera) (EPT taxa). Volunteers and authors collect 35 ultraviolet light traps during summer 2013 and supplementary benthic and adult sampling added species not attracted by lights or that were only present in colder months. Seventy-eight EPT species were recovered: 12 mayflies, two stoneflies, and 64 caddisflies. The EPT richness found at INDU was a low proportion of the number of species known from Indiana: caddisflies contributed only 32.7% of known state fauna, mayflies and stoneflies contributed 8.4% and 2.3%, respectively. Site EPT richness ranged from one for a seep to 34 for an 8 m-wide stream. Richness in streams generally increased with stream size. Seven new state records and rare species are reported. The number of EPT species at INDU is slightly larger than that found at Isle Royale National Park in 2013, and the community composition and evenness between orders were different.

Phylogenetic analyses suggest that diversification and body size evolution are independent in insects

BACKGROUND

Skewed body size distributions and the high relative richness of small-bodied taxa are a fundamental property of a wide range of animal clades. The evolutionary processes responsible for generating these distributions are well described in vertebrate model systems but have yet to be explored in detail for other major terrestrial clades. In this study, we explore the macro-evolutionary patterns of body size variation across families of Hexapoda (insects and their close relatives), using recent advances in phylogenetic understanding, with an aim to investigate the link between size and diversity within this ancient and highly diverse lineage.

RESULTS

The maximum, minimum and mean-log body lengths of hexapod families are all approximately log-normally distributed, consistent with previous studies at lower taxonomic levels, and contrasting with skewed distributions typical of vertebrate groups. After taking phylogeny and within-tip variation into account, we find no evidence for a negative relationship between diversification rate and body size, suggesting decoupling of the forces controlling these two traits. Likelihood-based modeling of the log-mean body size identifies distinct processes operating within Holometabola and Diptera compared with other hexapod groups, consistent with accelerating rates of size evolution within these clades, while as a whole, hexapod body size evolution is found to be dominated by neutral processes including significant phylogenetic conservatism.

CONCLUSIONS

Based on our findings we suggest that the use of models derived from well-studied but atypical clades, such as vertebrates may lead to misleading conclusions when applied to other major terrestrial lineages. Our results indicate that within hexapods, and within the limits of current systematic and phylogenetic knowledge, insect diversification is generally unfettered by size-biased macro-evolutionary processes, and that these processes over large timescales tend to converge on apparently neutral evolutionary processes. We also identify limitations on available data within the clade and modeling approaches for the resolution of trees of higher taxa, the resolution of which may collectively enhance our understanding of this key component of terrestrial ecosystems.

Ephemeroptera, Plecoptera, and Trichoptera on Isle Royale National Park, USA, compared to mainland species pool and size distribution

Extensive sampling for aquatic insects was conducted in the orders Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies) (EPT) of Isle Royale National Park (ISRO), Michigan, United States of America, during summer 2013. The island was ice covered until 8,000 to 10,000 years ago and is isolated by 22-70 km distance from the mainland. Two hypotheses were examined: that ISRO EPT richness would be much reduced from the mainland, and that the species colonizing ISRO would be of smaller size than mainland, adults presumably using updrafts to bridge the distance from mainland sources. Data sets were developed for known mainland EPT species and size for those species. The first hypothesis was confirmed with the mainland species pool consisting of 417 EPT, while ISRO is known to support 73 species. Richness of EPT is directly related to the number of specimens examined. Small streams supported five EPT species, while 15-25 species were found in larger streams. Lakeshores had intermediate diversity. The second hypothesis was substantiated for stoneflies, but not for mayflies or caddisflies. Stoneflies apparently are poorer fliers than either of the other two orders.

Seasonal changes in the critical thermal maxima of four species of aquatic insects (Ephemeroptera, Trichoptera)

Seasonal changes in the critical thermal maxima (CTmax) of four species of aquatic insects were determined from February 2012 to February 2013 from a first-order stream in northern Lower Michigan. Three of these species: Stenonema femoratum (Ephemeroptera: Heptageniidae), Hydropsyche slossonae (Trichoptera: Hydropsychidae), and Dolophilodes distinctus (Trichoptera: Philopotamidae) exhibited seasonal changes in CTmax, increasing through the spring and summer and then decreasing into the subsequent fall and winter. CTmax of these species correlated strongly with both the seasonal ambient stream temperature and with a series of different laboratory acclimation temperatures, suggesting that organisms adapt to laboratory acclimation in a similar manner as they adapt to seasonal changes. In contrast, the CTmax of Parapsyche apicalis (Trichoptera: Arctopsychidae) remained constant regardless of ambient or acclimation temperature. All species exhibited greater thermal sensitivity relative to ambient temperature during the summer than the winter. Our study indicates that thermal tolerance patterns can be different among species in the same environment. It also provides the first winter and year-round thermal tolerance data for aquatic insects.